1. Field of the Invention
The present invention relates to a method and apparatus for automatically aligning articles, for example, stacks of sliced ham as delivered stack by stack from a slicer, for supply to a packaging machine.
2. Description of the Prior Art
Ham loaves, when sliced by a slicer into ham slices having a thickness of, for example, about 2 or 3 mm each, are usually delivered from the slicing station in the form of ham stacks, each of plural slices (e. g., 5 to 10 slices). These ham stacks are supplied to a ham packaging machine or the like for vacuum packaging.
In order to achieve hygienic supply of, for example, ham stacks to a ham packaging machine, without requiring manual handling, a method for automatically feeding artcles in aligned condition is proposed in Japanese Patent Publication No. 58-24332.
According to this publication, a plurality of articles sequentially delivered in a line can be automatically aligned into position for transport toward the packaging machine and in corresponding relation to predetermined delivery positions at the packaging machine. More specifically, articles transported in a line on a transport conveyor are apportioned by a channelizer into laterally spaced parallel lines corresponding to article delivery positions at the packaging machine and are sequentially transferred onto a parallel transport conveyor. The parallel transport conveyor is pulsatively driven to run in such a way that articles, as they are transferred onto the conveyor, are sequentially carried forward a predetermined distance on the conveyor and then brought to a halt, which process is repeatedly carried out, so that the articles on the parallel transport conveyor are allowed to assume longitudinally and laterally spaced positions corresponding to the article delivery positions at the packaging machine. The thus aligned articles, while held as such, are then carried by catcher pawls of an article transfer device to a location above the article delivery positions at the packaging machine, being then released from the catcher pawls for transfer onto the delivery positions. According to this prior art method, means employed for transferring the aligned articles on the parallel transport conveyor, while they are held in alignment, to the delivery positions at the packaging machine comprises a pivot frame mounted posture-controlledly to free ends of pivotably supported parallel levers, an elevating frame up-and-down movably mounted to a lower portion of the pivot frame, and article catcher pawls attached to the elevating frame. In such method, it is necessary that articles must be clamped at least from lateral sides when they are to be transferred from the terminus of the parallel transport conveyor onto the packaging machine.
In case that the articles are, for example, ham stacks as mentioned above, therefore, the prior art technique involves a problem such that when ham stacks are clamped by the catcher pawls from lateral sides, the ham stacks may become deformed under the pressure of the catcher pawls or some slices of ham may fall off, because the underside of the articles is scarcely supported by the article transfer means during the process of the articles being transferred from the terminus of parallel transfer conveyor to the article delivery positions at the packaging machine. Another problem is that in the case where the clearances between aligned articles are very narrow, the catcher pawls can hardly simultaneously clamp the longitudinally and laterally aligned articles on the parallel transport conveyor.